(a) Field of the Invention
The present invention relates to an electromagnetic interference (EMI) cancellation method and system.
(b) Description of the Related Art
The term electromagnetic interference means any electromagnetic disturbance that interrupts, degrades, or limits the effective performance of electrical equipment or systems. In particular, high frequency electric noise emitted from an electric device via small integrated chips imparts a negative effect to neighboring components, and the equipment may also experience unwanted effects with the noise generated by neighboring devices.
The electromagnetic interference intensity depends on the operation speed of semiconductor devices, the power applied to a drive, the operational frequency of a signal, load impedance, wire length, distance to a bypass capacitor, etc.
In order to reduce electromagnetic interference, various techniques have been developed such as canceling noise to a power supply using a line filter, distributing noise by broadening a noise-inducing part during a switch operation, isolating noise-sensitive parts on a printed circuit board (PCB) pattern, and increasing ground size.
However, these techniques have drawbacks in that to install an additional noise cancellation device such as a line filter or to modify the PCB circuit pattern so as to broaden or isolate a specific part thereon increases the manufacturing cost and system complexity.